1. Field of the Invention
The present invention relates generally to an apparatus and a method for reducing heat in a wireless communication system. More particularly, the present invention relates to an apparatus and a method for reducing heat when forming a beam in the wireless communication system including a directional antenna.
2. Description of the Related Art
A base station of a wireless communication system includes a transceiver for processing transmitted and received signals, and an antenna for emitting a transmission signal and receiving a signal over the air. The transceiver includes a digital signal processor for processing a digital signal and an analog signal processor for processing an analog signal. The transceiver and the antenna are connected using a Radio Frequency (RF) cable. Accordingly, the base station is subject to loss from the RF cable. For example, when transmitting a signal, a power amplifier of the transmitter needs to amplify the signal to compensate for the loss of the RF cable. In doing so, a system cost increases. When the receiver receives a signal, the loss of the RF cable increases prior to a low noise amplifier. Thus, the noise of the receive signal also increases, thereby degrading system performance.
To address the disadvantages of the RF cable in a conventional wireless communication system, the base station is constructed by combining the antenna and the analog signal processor as shown in FIG. 1.
FIG. 1 illustrates a block diagram of a transceiver in a conventional wireless communication system. Hereafter, the base station of the wireless communication system is illustrated by way of example.
The base station of FIG. 1 includes a digital signal processor 100 and an RF signal processor 110.
The digital signal processor 100 processes a digital signal, to be sent, in baseband and provides the processed digital signal to the RF signal processor 110. The digital signal processor 100 also processes a baseband digital signal output from the RF signal processor 110.
The RF signal processor 110 includes a digital interface 111, an RF processor 113, a power amplifier 115, a Low Noise Amplifier (LNA) 117, a front end unit 119, and an antenna 121.
The digital interface 111 converts the digital signal fed from the digital signal processor 100 into an analog signal and outputs the analog signal to the RF processor 113. The digital interface 111 also converts an analog signal output from the RF processor 113 into a digital signal and outputs the digital signal to the digital signal processor 100.
The RF processor 113 converts the baseband signal output from the digital interface 111 into an RF signal and outputs the RF signal to the power amplifier 115. The RF processor 113 also converts an RF signal output from the LNA 117 into a baseband signal and outputs the baseband signal to the digital interface 111.
The power amplifier 115 amplifies the signal output from the RF processor 113 so as to transmit the transmission signal to a receiving end through a radio resource.
The LNA 117 amplifies the signal output from the front end unit 119 by reducing the noise of the signal.
The front end unit 119 separates a transmission path and a reception path. To transmit a signal, the front end unit 119 provides the signal from the power amplifier 115 to the antenna 121. To receive a signal, the front end unit 119 provides the signal from the antenna part 121 to the LNA 117.
The front end unit 119 eliminates spurious waves in a band other than the frequency band of the signal transmission and reception.
The antenna part 121 emits the transmission signal output from the front end unit 119 over the air or receives a radio signal and provides the received signal to the front end unit 119. When the antenna part 121 is implemented using a directional antenna, the antenna part 121 changes a phase and a gain with respect to the signal path of the antenna using a beamformer 123.
As discussed above, the wireless communication system includes the digital signal processor 100 and the RF signal processor 110 which are separated from each other. The wireless communication system can address the shortcomings of the RF cable by digitizing the connection between the digital signal processor 100 and the RF signal processor 110.
However, when the antenna and the analog signal processor are unified as a single module in the wireless communication system, the analog signal processor may be exposed to the elements. In this case, the analog signal processor may suffer from heat caused by solar radiation.
When beamforming, the beamformer 123 of the wireless communication system changes the phase and the gain of the signals, of which the power is amplified by the power amplifier, in the paths of the antennas. For doing so, the wireless communication system needs to construct the beamformer 123 with elements capable of processing the signal which has been amplified by the power amplifier. As a result, system cost is increased.